Conventionally, a ladder shaped chassis frame is provided in a small truck or a vehicle called a “sport-utility vehicle (SUV)” as described in, e.g., Patent Documents 1 and 2. The chassis frame is formed in the ladder shape by a pair of right and left main frames (also called “side frames”) extending in a vehicle length direction (vehicle longitudinal direction) and a plurality of cross-members each connecting the main frames together.
As described in Patent Documents 1 and 2, a suspension tower for supporting a top part of a strut of a front wheel suspension device may be attached to a front part of each of the main frames.